Scientists said today that the cause of
the deadly Ebola virus that hit West Africa this year was a 2 year old
boy, known as patient zero, who played on a tree near a colony of
virus-infested bats in his village in Meliandou,
Guinea. He was the first person to die but before he died, he infected
other family members, who then spread it to others and the virus
eventually spread into other areas in Guinea, Sierra Leone, Liberia, Nigeria and Senegal, before moving to the US, UK and Spain.

This Ebola outbreak is by far the
largest ever-recorded outbreak and it has killed about 7,800 people by
Dec. 17, 2014, according to WHO.